Drive unit for tandem aircraft engines



Oct. 30, 1928.

L. H.' RENGLER DRIVE UNIT FOR TANDEM AIRCRAFT ENGINES Filed Oct. 12. 1926 INVENTOR LYN/v ff. Rmau'n.

Patented 0a. 30, 192s. T

UNITED STATES PATENT orries.

LYNN H. RENGLER, OF LONG BEACH, CALIFORNIA..

DRIVE UNIT FOR TANDEM AIRCRAFT ENGINES.

Application filed October 12,1926. swarm. 141,063.

The present invention relates to improvements in a tandem engine compensating aircraft propeller drive unit in which cornpensating or differential gears, mechanical brakes, propeller drive shafts and propeller drive shaft gears and bearings are incorporated in an oil'tight gear case or housing which serves as a mounting for the two engines, the crank cases of the engines being bolted directly to the gear casing or housing; and the objects of the improvement are:

First; to provide equalization of the power and compensation for the variation in engine crank shaft speed, of two engines driv-' two engines, propeller shaft and propeller and an oil reservoir for lubricating the gears and bearings therein;

Fourth; to provide for variationsinpropeller gear ratio in relation to engine crank shaft speed by substitutlng propeller shaft driving gear and d fferential r1n or drivlng num o the opposite eng1ne,'the engine operating 1s 1 gear of different demensions an teeth for the regular gearsyand, I y

Fifth; to providea tan'de mengine, unit in which there is'no side draft when operating with one engine as the power is aways applied to center, and one propeller is used. Among other aims and objectsof this invention may be cited the provision of a de:

vice of the character described with a view to compactness and in which the number of parts are few, the construction simple and the cost of production relativelylow.

With these and numerous other objects in view, the invention resides in the construe-- tion, combination and arrangement of parts as will be hereinafter fully described, illus trated in the accompanying drawing, and pointed out in the claims hereunto appended.

One form of the invention is illustrated in the accompanying drawing, in which the figure is a horizontal section of the entire machine.

The oil tight gear casing or housing lis toaccommodate all gears, shafts, bearings, and controls and to can" the two engines which are bolted to the: anger; 2, 2,- their crank Starts 12,112 extending into the differential side gears 10 are splined at the ends and the hole through the center portionof the-diiferential side gears 10is machined to receive the splined ends of engine crank shafts 12, 12. The brake-drums 7, 7 are secured to the enginecrank shaft 12, 12. The brake bands 8,8 are carried bythe gear casing or housing 1 and are operated by controlrods 11; The differential cage or carrier 3 is carried on the annular and thrust bearings 6, 6, and the spider gears or pinions 9 'are attached to the differential cage or carrier 3 by means of the spider 15 and revolve with the same, While the differential side gears 10 are attached, to the crank shaft 12, 12 and revolve with the same. The propeller drive shaft gear 13 is secured to the propellerdrive shaft 4 and, engages with the differential ring or driving gear 14. The propeller drive shaft ler drive shaft 41 is tapered and machined to receive a standardhub.

To'start the engines, the brake 7 oneither '75 is carried in the annular and thrust bearings 5, 5'and the forward end of the propelengine is applied through the control rod 11 'thus prevent-ingthe crank shaft of this engine from revolving, the propeller isturned and the opposite engine is started in the usual 5 manner. -With this engine operating, to start accelerated and. suddenly throttled down and the brake on the dead engine is simultaneously released allowing the momentum of the propeller tocrank or start-said engine. With both engines operating, the operator manipulates the controls inisuch a manner that both engines are revolving at approximately the samespeed and sets the controls accordingly.

The compensating or differential gears compensate for any variation in revolutions per minute of'the two engines and also apply their power to the propeller drive shaft equally regardless of a variation of the speed of the two engines. In the event one of the engines becomes inoperative, the brake 7 is applied on the crank shaft of said inoperative engine preventing the same from revolving backward as itjwould have a tendency todo) and the opposite engine continues to drive the propeller at a reduced gear ratio or at one-half engine crank shaft speed (granting ratio between the gears 13 and 14 as l to 1).; Thefs'peed of ii i fi i is new increased or dmihlad the is able to. maintainits oruising speed or ap-' proximately so. vFor examplei with a one to one propeller shaft drive ratio and looth engines rotating at twelve hundred revolutions I per minute the 'propeller'is"also rotating'at twelve hundred revolutions per minute) the i a t ship is cruising at one'hundred nnlesper hour. Now, if one engineis stopped and the brake applied to the crank shaft,the other ilu iqfis Pe ut {t p op l r S d is de eased h ndre rsre etm p want b the snsm am leee r te to twenty-flour hundred revolutionsper minuteand the propeller is again rotating at tw.e. ye,llilz ifltfll ere ut i spD m te and thes ip e ains it sm ns' pe d. f e Hum dr dlm s pert e fwith .0 engine p ;ing-and theother stopped. Either engine imaysbeqii kly re ew d by d sw h controls and feed lines and removing nuts from, crankcase studs and another engine equa y. s@s y, ns l Thi m is P tim ar y, and s lr l er a p d to h remolde z ta r ra t in I the radial air-cooled engine which nr'u liy he usedwvith thisunit with ;a f e\v ehanges suoh as machining the crank it ;fiwleufi en i l d g 10 and therear of the latter crank case-bolted to the 2 gear case 1.; Orho th engines may be bolted in front of thecrank case to the gear case 1, or back of t l ieerank case to gear easel 40 by adjusting the engines in such a" manner that oneoperates clockwise and the other counter-clockwise, 1 F om th e q g i s tr ed yi pp e that I, have providedfan effioientand sub- ;5 stantial device of the character described and while'this specification manifests the de tails and preferred construction of the invention, I do not WlSl'l to be understood as v I V A p the crankcase and the fr ont j 35 ofthejorgrner crank bolted togear case land limiting myself to the specificdetails of construction and arrangements of parts here- 1n described and illustrated, as it ismanifest that variations and modifications maybe rev.2 2 .1 awem. Qfparts. a t adaptation of the device to various"conditions of use 'vvlthinve nt ion. lure-Mere reserve the right to all s ue h variations and modifications as'properly fall within the scope of my invehtion as hli afisr la in da ,.1.. ,1. '.'.1\ understood and, therefore, a more extended .ver planat lon'hasheen om tted.

', Having thu d scribed my intention \ivliat first} named 2. in a drive seam to in" the features'ref construction and out departing from the spirit and scope of the aidfena conStffi Ct-ion of 'ni invenatn be dearly eller' shaft," a Brake 

